Expression of estrogen and progesterone receptors and their mRNAs in ovarian endometriosis

To discover the molecular mechanisms of estrogen-induced growth in ovarian endometriosis, the expression of estrogen and progesterone receptors and their mRNAs was investigated. The expression of estrogen and progesterone receptors and their mRNAs was significantly (p < 0.01) lower in endometriotic endometria than in normal endometria. The ratio of estrogen receptors : progesterone receptors was significantly (p < 0.01) higher in the endometriotic tissues than in normal proliferative- and secretory-phase endometria, as was the ratio of their respective mRNAs. These findings suggest that the absolute and relatively reduced number of estrogen receptors in ovarian endometriosis might cause the loss of control of estrogenic action, and that, furthermore, the relatively increased number of progesterone receptors might lead to an estrogen-dominant milieu, assisting in the development and growth of the ovarian endometriosis.